1 Samuel 30:9-10; 1 Samuel 30:21-25

9 David and the 600 men with him went as far as the Wadi Besor, where where 200 men who were to remain behind would stop. 10 They stopped because they were too exhausted to cross the Wadi Besor. David and 400 of the men continued in pursuit.
21 When David came to the 200 men who had been too exhausted to go with him and had been left at the Wadi Besor, they came out to meet him and to meet the troops with him. When David approached the men, he greeted them, 22 but all the worthless men among those who had gone with David retorted, "Because they didn't go with us, we will not give any of the plunder we recovered to them except for each man's wife and children. They may take them and go." 23 But David said, "My brothers, you must not do this with what the Lord has given us. He protected us and handed over to us the raiders who came against us. 24 Who can agree to your proposal? The share of the one who goes into battle is to be the same as the share of the one who remains with the supplies. They will share equally." 25 And it has been so from that day forward. David established [this policy] as a law and an ordinance for Israel [and it continues] to this very day.